KR20140054034A - Method and apparatus for transmitting and receiving frame on the basis of frequency selection transmission - Google Patents

Method and apparatus for transmitting and receiving frame on the basis of frequency selection transmission Download PDF

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KR20140054034A
KR20140054034A KR1020147003346A KR20147003346A KR20140054034A KR 20140054034 A KR20140054034 A KR 20140054034A KR 1020147003346 A KR1020147003346 A KR 1020147003346A KR 20147003346 A KR20147003346 A KR 20147003346A KR 20140054034 A KR20140054034 A KR 20140054034A
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frame
receiver
subchannel
channel
sta
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KR1020147003346A
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KR101607411B1 (en
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박종현
유향선
석용호
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엘지전자 주식회사
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Priority to PCT/KR2012/006255 priority patent/WO2013022254A2/en
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/02Selection of wireless resources by user or terminal
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/24Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2603Arrangements for wireless physical layer control
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/24Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2612Arrangements for wireless medium access control, e.g. by allocating physical layer transmission capacity
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/12Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18Automatic repetition systems, e.g. van Duuren system ; ARQ protocols
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/0001Arrangements for dividing the transmission path
    • H04L5/0003Two-dimensional division
    • H04L5/0005Time-frequency
    • H04L5/0007Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0037Inter-user or inter-terminal allocation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0058Allocation criteria
    • H04L5/006Quality of the received signal, e.g. BER, SNR, water filling
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W56/00Synchronisation arrangements
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/04Wireless resource allocation
    • H04W72/08Wireless resource allocation where an allocation plan is defined based on quality criteria
    • H04W72/085Wireless resource allocation where an allocation plan is defined based on quality criteria using measured or perceived quality
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems
    • H04B7/0417Feedback systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems
    • H04B7/0452Multi-user MIMO systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/12Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18Automatic repetition systems, e.g. van Duuren system ; ARQ protocols
    • H04L1/1829Arrangements specific to the receiver end
    • H04L1/1861Physical mapping arrangements
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2602Signal structure
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W4/00Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/06Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
    • H04W4/08User group management
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/04Wireless resource allocation
    • H04W72/044Wireless resource allocation where an allocation plan is defined based on the type of the allocated resource
    • H04W72/0446Wireless resource allocation where an allocation plan is defined based on the type of the allocated resource the resource being a slot, sub-slot or frame

Abstract

Provided is a method for transmitting a data frame through a channel including a plurality of sub-channels by a sender in a wireless local area network system. The method comprises the steps of: acquiring first channel state information on each of the sub-channels from a first receiver; allocating at least one first allocation sub-channel of the plurality of sub-channels to the first receiver on the basis of the first channel state information; acquiring second channel state information on each of the plurality of sub-channels from a second receiver if the at least one first allocation sub-channel corresponds to a portion of a plurality of channels; allocating at least one second allocation sub-channel of the sub-channels to the second receiver on the basis of the second channel state information; and transmitting a data unit to the first receiver and the second receiver. The data unit includes a first data frame and a second data frame, wherein the first data frame is transmitted through the at least one first allocation sub-channel, and the second data frame is transmitted through the at least one second allocation sub-channel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for transmitting and receiving frames based on frequency selective transmission,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to wireless communication, and more particularly, to a method for transmitting and receiving a frame based on a frequency selection by a station in a wireless LAN system and an apparatus for supporting the same.

Recently, various wireless communication technologies have been developed along with the development of information communication technologies. Among these, a wireless local area network (WLAN) uses a portable terminal such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP) To connect to the Internet wirelessly in homes, businesses, or specific service delivery areas.

IEEE 802.11n is a relatively recently established technical standard to overcome the limitation of communication speed which is pointed out as a weak point in wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and to extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with data rates of up to 540 Mbps or higher, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology.

Meanwhile, according to the activation of the wireless LAN, a single AP provides a service to a very large number of non-AP stations. The characteristics of a wireless LAN supporting such an environment can be represented by low data rate, low power and wide coverage. For this, devices operating in the wireless LAN environment can transmit and receive wireless signals using a lower frequency band.

By using a low frequency band, the channel bandwidth used for transmitting and receiving radio signals can be narrower than when using a conventional high frequency band. When a narrowband channel is used as described above, a new discussion on data transmission and reception may be required regarding the channel access method and the interference avoiding method.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a data transmission / reception method based on frequency selective transmission in a wireless local area network (WLAN) system and a device supporting the same.

In one aspect, a method of transmitting a data frame over a channel including a plurality of subchannels performed by a sender in a wireless LAN system is provided. The method comprising: obtaining first channel state information for each of the plurality of subchannels from the first receiver; Allocating at least one first allocated subchannel among the plurality of subchannels to a first receiver based on the first channel state information; Acquiring second channel state information for each of the plurality of subchannels from the second receiver if the at least one first allocated subchannel corresponds to a portion of the plurality of channels; Allocating at least one second assigned subchannel among the plurality of subchannels to a second recipient based on the second channel state information; And transmitting the data unit to the first receiver and the second receiver. Wherein the data unit comprises a first data frame and a second data frame, the first data frame is transmitted on the at least one first allocated subchannel and the second data frame is transmitted over the at least one second assignment Subchannel.

The data unit may further include a preamble part, and the preamble may include subchannel allocation indication information indicating a subchannel allocated to the first receiver and the second receiver.

The first channel state information may include an estimated SNR (Signal to Noise Ratio) between the sender and the first receiver for each subchannel. The second channel state information may include an estimated SNR between the sender and the second receiver for each subchannel.

Assigning the at least one first allocated subchannel to the first receiver may be assigning a particular subchannel with the highest estimated SNR to the first assigned subchannel between the sender and the first receiver .

Wherein allocating the at least one first allocated subchannel to the first recipient comprises allocating at least one or more subchannels with an estimated SNR higher than a certain threshold value between the sender and the first recipient to the first assigned subchannel It may be to assign.

The obtaining of the first channel state information includes: transmitting an NDPA (NDP Announcement) frame indicating that NDP (Null Data Packet) for channel sounding is transmitted; Transmit the NDP; And receiving a first feedback frame including the first status channel information obtained based on the NDP from the first receiver.

Wherein the obtaining of the second channel state information comprises: transmitting a feedback poll frame to the second receiver indicating to report the second channel state information; And receiving a second feedback frame including the second status channel information obtained based on the NDP from the second receiver.

The NDPA frame may include information identifying the first receiver and the second receiver, which are recipients of the channel sounding.

The NDPA frame may be transmitted in a duplicated data unit format transmitted simultaneously through each of the plurality of subchannels.

The NDP may be transmitted in the replicated data unit format transmitted via each of the plurality of subchannels.

The at least one second allocated subchannel may be selected from among the plurality of subchannels except for the at least one first allocated subchannel.

The method may further comprise transmitting the first data frame to the first receiver over the channel if the at least one first allocated subchannel is allotted to all of the plurality of channels.

The method comprising: receiving a first acknowledgment frame in response to the first data frame on the at least one first allocated subchannel; And receiving a second acknowledgment frame in response to the second data frame on the at least one second allocated subchannel.

The first acknowledgment frame and the second acknowledgment frame may be transmitted simultaneously.

In another aspect, a wireless device operating in a wireless LAN system is provided. The wireless device comprising: a transceiver for transmitting and receiving wireless signals over a channel including a plurality of subchannels; And a processor operatively coupled to the transceiver. Wherein the processor is operable to obtain first channel state information for each of the plurality of subchannels from the first receiver and to allocate at least one first allocated subchannel among the plurality of subchannels based on the first channel state information And if the at least one first allocated subchannel corresponds to a part of the plurality of channels, acquires second channel state information for each of the plurality of subchannels from the second receiver, And allocates at least one second subchannel of the plurality of subchannels to a second receiver based on the two-channel state information and transmits the data unit to the first receiver and the second receiver. Wherein the data unit comprises a first data frame and a second data frame, the first data frame is transmitted on the at least one first allocated subchannel and the second data frame is transmitted over the at least one second assignment Subchannel.

The AP can acquire channel state information on subchannels between individual STAs and APs through a channel sounding procedure. The AP may determine an appropriate subchannel to use for transmitting data frames to a specific STA based on the channel state information of the subchannel. The AP may transmit the data frame to the at least one STA through the DL-FDMA scheme through the allocated subchannel. The AP may selectively allocate a channel with a good state to a specific STA, thereby transmitting a data frame to at least one STA. The data frame transmission method improves the reliability of data transmission and reception and improves the throughput of the entire WLAN system.

1 is a diagram illustrating a configuration of a wireless local area network (WLAN) system to which an embodiment of the present invention can be applied.
2 is a diagram illustrating a physical layer architecture of a wireless LAN system supported by IEEE 802.11.
3 and 4 are block diagrams illustrating a format of a PPDU used in a wireless local area network (LAN) system to which the embodiment of the present invention can be applied.
5 is a diagram illustrating a channel sounding method using an NDP in a next generation wireless LAN system.
6 is a diagram illustrating an example of channelization of an M2M wireless LAN system according to each country / region band plan.
FIG. 7 is a diagram illustrating a concept of a frequency selective channel access mechanism in a narrowband frequency environment of an M2M wireless LAN system according to an embodiment of the present invention. Referring to FIG.
8 is a diagram illustrating an example of a channel used in a wireless LAN system according to an embodiment of the present invention.
9 is a diagram illustrating a DL-FDMA-based frame transmission / reception method according to an embodiment of the present invention.
10 is a block diagram illustrating a wireless device to which an embodiment of the present invention may be applied.

1 is a diagram illustrating a configuration of a wireless local area network (WLAN) system to which an embodiment of the present invention can be applied.

Referring to FIG. 1, a WLAN system includes one or more Basic Service Sets (BSSs). BSS is a set of stations (STAs) that can synchronize successfully and communicate with each other,

The infrastructure BSS may include one or more non-AP stations (non-AP STA1 21, non-AP STA2 22, non-AP STA3 23, non-AP STA4 24, (STAa 30), an access point (AP) 10 for providing a distribution service, and a distribution system (DS) for connecting a plurality of APs. In the infrastructure BSS, the AP manages the non-AP STAs of the BSS.

On the other hand, an independent BSS (IBSS) is a BSS operating in an ad-hoc mode. Since the IBSS does not include APs, there is no centralized management entity in the center. That is, non-AP STAs are managed in a distributed manner in the IBSS. In the IBSS, all STAs can be made as mobile STAs, and self-contained networks are established because access to the DS is not allowed.

The STA is an arbitrary functional medium including a medium access control (MAC) conforming to IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard and a physical layer interface for a wireless medium. It includes both an AP and a non-AP station.

The non-AP STA is a non-AP STA, the non-AP STA is a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE) May also be referred to as another name, such as a mobile station (MS), a mobile subscriber unit, or simply a user. Hereinafter, non-AP STA will be referred to as STA for convenience of explanation.

An AP is a functional entity that provides access to a DS via wireless media for an associated STA to the AP. Communication between STAs in an infrastructure BSS including an AP is performed via an AP, but direct communication is also possible between STAs when a direct link is established. The AP may be referred to as a central controller, a base station (BS), a node-B, a base transceiver system (BTS), a site controller or a management STA.

A plurality of infrastructure BSSs including the BSS shown in FIG. 1 may be interconnected through a distribution system (DS). A plurality of BSSs connected through a DS is referred to as an extended service set (ESS). The APs and / or STAs included in the ESS can communicate with each other, and the STA can move from one BSS to another BSS while continuing to communicate in the same ESS.

In a wireless LAN system according to IEEE 802.11, the basic access mechanism of Medium Access Control (MAC) is a CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also referred to as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, which basically employs a "listen before talk" access mechanism. According to this type of connection mechanism, the AP and / or STA senses a wireless channel or medium prior to initiating a transmission. As a result of sensing, if it is determined that the medium is in the idle status, the frame transmission is started through the medium. On the other hand, if it is detected that the medium is occupied, the AP and / or STA sets a delay period for medium access without waiting to start its own transmission.

The CSMA / CA mechanism also includes virtual carrier sensing in addition to physical carrier sensing in which the AP and / or STA directly senses the media. Virtual carrier sensing is intended to compensate for problems that may arise from media access, such as hidden node problems. For the virtual carrier sensing, the MAC of the wireless LAN system uses a network allocation vector (NAV). The NAV is a value indicating to another AP and / or the STA that the AP and / or the STA that is currently using or authorized to use the medium has remaining time until the media becomes available. Therefore, the value set to NAV corresponds to the period in which the medium is scheduled to be used by the AP and / or the STA that transmits the frame.

In addition to DCF, the IEEE 802.11 MAC protocol is a DCF and pollination-based, synchronous access scheme that uses an HCF (Point Coordination Function) that periodically polls all receiving APs and / or STAs to receive data packets. (Hybrid Coordination Function). The HCF is a protocol that allows a provider to provide data packets to a large number of users using a competing based EDCA (Enhanced Distributed Channel Access) and a non-contention based channel approach using a polling mechanism (HCCA Access). The HCF includes a medium access mechanism for improving QoS (Quality of Service) of a wireless LAN and can transmit QoS data in both a contention period (CP) and a contention free period (CFP).

In the wireless communication system, the presence of the network is not immediately known when the power of the STA is turned on and the operation is started due to the characteristics of the wireless medium. Therefore, any type of STA must perform a network discovery process in order to access the network. The STA that detects the network through the network discovery process selects the network to join through the network selection process. Thereafter, the mobile station joins the selected network and performs a data exchange operation in the transmission / reception stage.

In the wireless LAN system, the network discovery process is implemented by a scanning procedure. The scanning procedure is divided into passive scanning and active scanning. Manual scanning is based on a beacon frame in which the AP periodically broadcasts. Generally, an AP in a wireless LAN broadcasts a beacon frame every predetermined interval (for example, 100 msec). The beacon frame contains information about the BSS that it manages. The STA manually waits for a beacon frame to be received on a particular channel. The STA that has acquired the information about the network through the reception of the beacon frame terminates the scanning procedure in the specific channel. Manual scanning is advantageous in that the overall overhead is small since the STA only needs to receive a beacon frame without having to transmit a separate frame. However, there is a disadvantage in that the scanning execution time is increased in proportion to the transmission period of the beacon frame.

In active scanning, the STA actively broadcasts a probe request frame on a specific channel and requests network information from all the APs that receive the probe request frame. After receiving the probe request frame, the AP transmits a network response to the probe response frame after waiting for a random time to prevent frame collision. The STA terminates the scanning procedure by receiving the probe response frame and obtaining the network information. Active scanning has the advantage that scanning can be completed in a relatively short time. On the other hand, since the frame sequence according to the request-response is required, the overall network overhead increases.

After completing the scanning procedure, the STA selects a network according to a specific criterion for itself and performs an authentication procedure with the AP. The authentication procedure consists of a two-way handshake. After completing the authentication procedure, the STA proceeds with the association process with the AP.

The combining procedure consists of a two-way handshake. First, the STA sends an association request frame to the AP. The association request frame includes capability information of the STA. Based on this, the AP determines whether the STA can be combined. The AP which has decided whether to allow the association transmits an association response frame to the corresponding STA. The association response frame includes information indicating whether or not to permit the association and information indicating the reason for the combination permission / failure. The association response frame further includes information on the capability values that the AP can support. If the association is successfully completed, a normal frame exchange is performed between the AP and the STA. If the association fails, the association procedure may be retried based on information about the reason for the failure included in the association response frame, or the STA may request the association to another AP.

IEEE 802.11n is a relatively recently established technical standard to overcome the limitation of communication speed which is pointed out as a weak point in wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and to extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with data rates of up to 540 Mbps or higher, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology.

STA has been actively promoting the dissemination of wireless LANs and diversifying applications using them. Recently, there is a need for a new wireless LAN system to support a higher throughput than the data processing rate supported by IEEE 802.11n. The wireless LAN system supporting Very High Throughput (VHT) is the next version of the IEEE 802.11n wireless LAN system. It has a data processing speed of more than 1Gbps for multiuser in MAC Service Access Point (SAP) And is one of the recently proposed IEEE 802.11 wireless LAN systems to support a throughput of 500 Mbps or higher for a single user.

To support 80MHz continuous 160MHz (contiguous 160MHz), discrete 160MHz (non-contiguous 160MHz) bandwidth transmission and / or higher bandwidth transmission in VHT Wireless LAN system than existing wireless LAN system supporting 20MHz and 40MHz do. In addition, it supports 256QAM more than existing wireless LAN system supporting 64QAM (Quadrature Amplitude Modulation).

In the VHT wireless LAN system, since the MU-MIMO (Multi User-Multiple Input Multiple Output) transmission method is supported for higher throughput, the AP can simultaneously transmit data frames to at least one STA paired with MIMO. The number of paired STAs can be a maximum of four, and when the maximum number of spatial streams is eight, each STA can be assigned a maximum of four spatial streams.

Referring to FIG. 1 again, in the given WLAN system, the AP 10 includes at least one STA among a plurality of STAs 21, 22, 23, 24, and 30 associated therewith The data can be simultaneously transmitted to the STA group. 1 illustrates an example in which an AP transmits MU-MIMO to STAs. However, in a wireless LAN system supporting TDLS (Tunneled Direct Link Setup), DLS (Direct Link Setup), and mesh network, The STA can transmit the PPDU to a plurality of STAs using the MU-MIMO transmission scheme. Hereinafter, the AP transmits an PPDU to a plurality of STAs according to the MU-MIMO transmission scheme.

Data transmitted to each STA may be transmitted through different spatial streams. The data packet transmitted by the AP 10 may be referred to as a frame as a data field included in a PPDU or PPDU generated and transmitted in the physical layer of the WLAN system. That is, a data field included in a PPDU or PPDU for SU (single user) -MIMO and / or MU-MIMO may be referred to as a MIMO packet. Among them, the PPDU for the MU can be called an MU packet. In the example of the present invention, it is assumed that STA1 21, STA2 22, STA3 23 and STA4 24 are STA groups that are paired with AP 10 and MU-MIMO. At this time, since a spatial stream is not allocated to a specific STA of a transmission target STA group, data may not be transmitted. On the other hand, it is assumed that the STAa 30 is an STA that is coupled to the AP but is not included in the STA group to be transmitted.

Table 1 below shows the information elements included in the group ID management frame.

Figure pct00001

The category field and the VHT action field are set so that the corresponding frame corresponds to a management frame and is a group ID management frame used in a next-generation wireless LAN system supporting MU-MIMO.

As shown in Table 1, the group definition information indicates membership status information indicating whether or not it belongs to a specific group ID, and when it belongs to the group ID, the spatial stream set of the STA is located at a certain position in the entire spatial stream according to the MU- And the spatial stream position information indicating whether it is applicable.

Since there are a plurality of group IDs managed by one AP, the membership status information provided to one STA needs to indicate whether each STA belongs to each group ID managed by the AP. Thus, the membership state information may exist in the form of an array of subfields indicating whether or not they belong to each group ID. The spatial stream location information indicates a location for each group ID, and therefore may exist in the form of an array of subfields indicating the location of the spatial stream set occupied by the STA for each group ID. In addition, the membership state information and the spatial stream position information for one group ID can be implemented in one subfield.

When transmitting the PPDU to the plurality of STAs through the MU-MIMO transmission scheme, the AP transmits information indicating the group ID (Group ID) as control information in the PPDU. When the STA receives the PPDU, the STA checks the group ID field to confirm that the STA is the member STA of the STA group to be transmitted. If it is confirmed that the STA group is a member of the STA group to which the STA is to be transmitted, it is possible to confirm how many spatial stream sets transmitted to the STA group are located among the entire spatial streams. Since the PPDU includes information on the number of spatial streams allocated to the receiving STA, the STA can receive data by searching for the spatial streams assigned to the receiving STA.

On the other hand, TV WS (white space) is attracting attention as a frequency band that can be newly used in a wireless LAN system. The TV WS refers to a dormant frequency band that remains due to the digitization of analog TV in the United States, for example, the band 54 to 698 MHz. However, this is merely an example, and the TV WS may be an authorized band that the licensed user can use first. An authorized user means a user who is authorized to use the licensed band, and may also be called another name, such as a licensed device, a primary user, an incumbent user, and so on.

The AP and / or STA operating on the TV WS should provide protection for the authorized user because the user authorized in the use of the TV WS band takes precedence. For example, when an authorized user such as a microphone already uses a specific WS channel, which is a conventionally divided frequency band having a specific bandwidth in the TV WS band, the AP and / Or the STA can not use the frequency band corresponding to that WS channel. In addition, the AP and / or the STA should stop using the frequency band currently used for frame transmission and / or reception when the authorized user uses the frequency band.

Therefore, the AP and / or the STA must precede the procedure of determining whether a specific frequency band in the TV WS band is available, in other words, whether there is a user authorized in the frequency band. Knowing whether or not there is a user authorized in a specific frequency band is called spectrum sensing. The spectrum sensing mechanism uses energy detection method and signature detection method. If the strength of the received signal is equal to or greater than a predetermined value, it is determined that the authorized user is in use, or it is determined that the authorized user is using the DTV preamble when the preamble is detected.

2 is a diagram illustrating a physical layer architecture of a wireless LAN system supported by IEEE 802.11.

The PHY architecture of IEEE 802.11 includes a PHY Layer Management Entity (PLME), a Physical Layer Convergence Procedure (PLCP) sublayer 210, and a PMD (Physical Medium Dependent) sublayer 200. PLME provides the management functions of the physical layer in cooperation with the MAC Layer Management Entity (MLME). The PLCP sublayer 210 transmits an MPDU (MAC Protocol Data Unit) received from the MAC sublayer 220 to the PMD sublayer according to an instruction of the MAC layer between the MAC sublayer 220 and the PMD sublayer 200 , And delivers the frame from the PMD sublayer 200 to the MAC sublayer 220. The PMD sublayer 200 enables the transmission / reception of a physical layer entity between two stations via a wireless medium as a PLCP lower layer. The MPDU transmitted from the MAC sublayer 220 is referred to as a physical service data unit (PSDU) in the PLCP sublayer 210. MPDUs are similar to PSDUs, but individual MPDUs and PSDUs can be different when an aggregated MPDU (aggregated MPDU) aggregating multiple MPDUs is delivered.

The PLCP sublayer 210 adds an additional field including information required by the physical layer transceiver in the process of receiving the PSDU from the MAC sublayer 220 and transferring the PSDU to the PMD sublayer 200. In this case, the added field may be a PLCP preamble, a PLCP header, a tail bit for returning the convolutional encoder to a zero state, or the like, to the PSDU. The PLCP sublayer 210 receives a TXVECTOR parameter including control information necessary for generating and transmitting a PPDU and control information necessary for the receiving STA to receive and interpret the PPDU from the MAC sublayer. The PLCP sublayer 210 uses the information included in the TXVECTOR parameter in generating the PPDU including the PSDU.

The PLCP preamble serves to prepare the receiver for the synchronization function and antenna diversity before the PSDU is transmitted. The data field may include padding bits in the PSDU, a service field including a bit sequence for initializing the scrap blur, and a coded sequence in which a bit sequence with tail bits appended thereto is encoded. In this case, the encoding scheme may be selected from Binary Convolutional Coding (BCC) encoding or Low Density Parity Check (LDPC) encoding according to the encoding scheme supported by the STA receiving the PPDU. The PLCP header includes a field including information on a PLCP Protocol Data Unit (PPDU) to be transmitted. This will be described in more detail with reference to FIGS. 3 to 5. FIG.

In the PLCP sublayer 210, the above-described field is added to the PSDU to generate a PLCP Protocol Data Unit (PPDU) and transmitted to the receiving station via the PMD sublayer. The receiving station receives the PPDU and generates a PLCP preamble, data Get and restore the information needed for restoration. The PLCP sublayer of the receiving station transmits the RXVECTOR parameter including the PLCP preamble and control information included in the PLCP header to the MAC sublayer to interpret the PPDU in the receiving state and acquire the data.

3 and 4 are block diagrams illustrating a format of a PPDU used in a wireless local area network (LAN) system to which the embodiment of the present invention can be applied. Hereinafter, a STA operating in a legacy wireless LAN system based on IEEE 802.11a / b / g, which is an existing wireless LAN standard prior to IEEE 802.11n, is referred to as a legacy STA (Legacy STA). In addition, STA that can support HT in HT Wireless LAN system based on IEEE 802.11n is called HT-STA.

3 shows a legacy PPDU (L-PPDU) format, which is a PPDU used in IEEE 802.11a / b / g, which is a conventional wireless LAN system standard prior to IEEE 802.11n. Accordingly, in an HT wireless LAN system adopting the IEEE 802.11n standard, a legacy STA (L-STA) can transmit and receive L-PPDUs having such a format.

Referring to FIG. 3A, the L-PPDU 310 includes an L-STF 311, an L-LTF 312, an L-SIG field 313, and a data field 314.

The L-STF 311 is used for frame timing acquisition, automatic gain control (AGC) convergence, coarse frequency acquisition, and the like.

The L-LTF 312 is used for frequency offset and channel estimation.

The L-SIG field 313 includes control information for demodulating and decoding the data field 314.

(B) is a block diagram of an HT-mixed PPDU format allowing L-STA and HT-STA to coexist. Referring to FIG. 6B, the HT mixed PPDU 320 includes an L-STF 321, an L-LTF 322, an L-SIG 323, an HT-SIG 324, A plurality of HT-LTFs 326 and a data field 327.

The L-STF 321, the L-LTF 322 and the L-SIG field 323 are the same as those indicated by reference numerals 311, 312 and 313 in FIG. Thus, the L-STA may interpret the data field via the L-LTF 322, the L-LTF 322, and the L-SIG 323 upon receiving the HT mixed PPDU 320. However, the L-LTF field 323 indicates the channel to be performed by the HT-STA to receive the HT mixed PPDU 320 and decode the L-SIG field 323, the HT-SIG 324, and the HT- And may further include information for estimation.

The HT-STA can know that the HT mixed PPDU 320 is a PPDU for itself through the HT-SIG 324 following the L-SIG 323 and demodulate and decode the data field 327 based on the information .

The HT-STF 325 may be used for frame timing synchronization, AGC convergence, etc. for the HT-STA.

The HT-LTF 326 may be used for channel estimation for demodulation of the data field 327. Since IEEE 802.11n supports SU-MIMO, a plurality of HT-LTFs 326 can be configured for channel estimation for each data field transmitted in a plurality of spatial streams.

The HT-LTF 326 may comprise a Data HT-LTF used for channel estimation for spatial streams and an extended HT-LTF (Extension HT-LTF) used additionally for full channel sounding have. Thus, the plurality of HT-LTFs 326 may be equal to or greater than the number of spatial streams transmitted.

The L-STF 321, the L-LTF 322, and the L-SIG field 323 are transmitted first so that the HT-mixed PPDU 320 can also receive the L-STA and acquire the data. The HT-SIG field 324 is then transmitted for demodulation and decoding of data transmitted for the HT-STA.

STA and HT-STA to receive the corresponding PPDU to acquire data, and transmits the HT-STF 325, HT-SIG 324, and HT- The LTF 326 and the data field 327 are subjected to wireless signal transmission through precoding. Herein, the STA 323 transmits a plurality of HT-LTFs 326 and a plurality of data fields 327 to transmit the HT-STFs 325 in order to allow the receiving STAs to take into account the variable power by precoding. do.

Although the HT-STA using 20 MHz in the HT-WLAN system uses 52 data subcarriers per OFDM symbol, the L-STA using the same 20 MHz still uses 48 data subcarriers per OFDM symbol. Since the HT-SIG field 324 in the HT mixed PPDU 320 format is decoded using the L-LTF 322 to support backward compatibility with the existing system, the HT-SIG field 324 is 48 × 2 data subcarriers. The HT-STF 325 and the HT-LTF 426 are configured with 52 data subcarriers per OFDM symbol. As a result, since the HT-SIG field 324 is 1/2 and BPSK (Binary Phase Shift Keying), each HT-SIG field 324 is composed of 24 bits and is transmitted in a total of 48 bits. That is, the channel estimation for the L-SIG field 323 and the HT-SIG field 324 uses the L-LTF 322 and the bit sequence constituting the L-LTF 322 is expressed by the following Equation 1 . The L-LTF 322 is composed of 48 data subcarriers excluding a DC subcarrier per symbol.

Figure pct00002

(C) is a block diagram showing an HT-Greenfield PPDU 330 format that only the HT-STA can use. Referring to FIG. 3C, the HT-GF PPDU 330 includes an HT-GF-STF 331, an HT-LTF1 332, an HT- SIG 333, a plurality of HT- (335).

The HT-GF-STF 331 is used for frame timing acquisition and AGC.

HT-LTF1 332 is used for channel estimation.

The HT-SIG 333 is used for demodulating and decoding the data field 335.

The HT-LTF2 334 is used for channel estimation for demodulation of the data field 335. Likewise, since the HT-STA uses SU-MIMO, channel estimation is required for each of the data fields transmitted in a plurality of spatial streams, so that the HT-LTF 326 can be composed of a plurality of channels.

The plurality of HT-LTFs 334 may be composed of a plurality of Data HT-LTFs and a plurality of extended HT-LTFs, similar to the HT-LTFs 326 of the HT mixed PPDUs 320.

Each of the data fields 314, 327, and 335 shown in Figures (a), (b), and (c) may include a service field, a scrambled PSDU, a tail bit, and a padding bit. The service field may be used to initialize the scrambler. The service field may be set to 16 bits. In this case, the bits for scrambler initialization can be implemented with 7 bits. The tail field may consist of a bit sequence necessary to return the convolution encoder to a zero state. Bit size proportional to the number of BCC (Binary Convolutional Code) encoders used to encode the data to be transmitted, and more specifically, can be implemented to have 6 bits per BCC number.

4 is a diagram showing an example of a PPDU format used in a wireless LAN system supporting VHT.

4, the PPDU 400 includes an L-STF 410, an L-LTF 420, an L-SIG field 430, a VHT-SIGA field 440, a VHT- STF 450, LTF 460, VHT-SIGB field 470, and data field 480.

The PLCP sublayer constituting the PHY adds necessary information to the PSDU received from the MAC layer and converts it into a data field 480. The L-STF 410, the L-LTF 420, the L-SIG field 430, The PPDU 400 is added by adding the fields of the -SIGA field 440, the VHT-STF 450, the VHT-LTF 460, and the VHT-SIGB 470, To the STA. The control information used for the PPDU to be generated by the PLCP sublayer and included in the PPDU, and the control information used by the receiving STA to interpret the PPDU are provided from the TXVECTOR parameter received from the MAC layer.

The L-STF 410 is used for frame timing acquisition, automatic gain control (AGC) convergence, coarse frequency acquisition, and the like.

The L-LTF 420 is used for channel estimation for demodulation of the L-SIG field 430 and the VHT-SIGA field 440.

The L-SIG field 430 is used by the L-STA to receive the PPDU 400 and interpret it to obtain data. The L-SIG field 430 includes a rate sub-field, a length sub-field, a parity bit, and a tail field. The rate subfield is set to a value indicating a bit rate for the data to be currently transmitted.

The length subfield is set to a value indicating the octet length of the PSDU requesting the MAC layer to transmit to the PHY layer. The L_LENGTH parameter, which is a parameter related to the octet length information of the PSDU, is determined based on the TXTIME parameter, which is a parameter related to the transmission time. TXTIME indicates a transmission time determined by the PHY layer for transmission of a PPDU including a PSDU in response to a transmission time requested by the MAC layer for transmission of a physical service data unit (PSDU). Therefore, since the L_LENGTH parameter is a time-related parameter, the length subfield included in the L-SIG field 430 includes information related to the transmission time.

The VHT-SIGA field 440 contains control information (or signal information) necessary for the STAs receiving the PPDU to interpret the PPDU 400. The VHT-SIGA field 440 is transmitted in two OFDM symbols. Accordingly, the VHT-SIGA field 440 can be divided into the VHT-SIGA1 field and the VHT-SIGA2 field. The VHT-SIGA1 field includes channel bandwidth information used for PPDU transmission, identification information related to whether or not Space Time Block Coding (STBC) is used, information indicating a method of transmitting a PPDU among SU or MU-MIMO, In the case of MU-MIMO, information indicating a STA group to be transmitted, which is a plurality of STAs paired with an AP and an MU-MIMO, and information on a spatial stream allocated to each STA included in the STA group to be transmitted. The VHT-SIGA2 field contains short GI (Short Guard Interval) related information.

The information indicating the MIMO transmission scheme and the information indicating the STA group to be transmitted may be implemented as one MIMO indication information, and may be implemented as a group ID, for example. The group ID may be set to a value having a specific range, and a specific value in the range indicates the SU-MIMO transmission scheme. Otherwise, when the PPDU 400 is transmitted in the MU-MIMO transmission scheme, It can be used as an identifier for STA group.

If the group ID indicates that the corresponding PPDU 400 is transmitted through the SU-MIMO transmission scheme, the VHT-SIGA2 field indicates whether the coding scheme applied to the data field is Binary Convolution Coding (BCC) or Low Density Parity Check (LDPC) And modulation coding scheme (MCS) information for the channel between the sender and the receiver. Further, the VHT-SIGA2 field may include a partial AID (partial AID) including an AID of a transmission target STA of the PPDU and / or a partial bit sequence of the AID.

When the group ID indicates that the corresponding PPDU 400 is transmitted through the MU-MIMO transmission scheme, the VHT-SIGA field 440 indicates that the coding scheme applied to the data field to which transmission is intended to the MU-MIMO paired receiving STAs is BCC Coding instruction or LDPC coding. In this case, modulation coding scheme (MCS) information for each receiving STA may be included in the VHT-SIGB field 470.

The VHT-STF 450 is used to improve the performance of the AGC estimation in the MIMO transmission.

The VHT-LTF 460 is used by the STA to estimate the MIMO channel. Since the next generation wireless LAN system supports MU-MIMO, the VHT-LTF 460 can be set to the number of spatial streams to which the PPDU 400 is transmitted. In addition, full channel sounding is supported, and the number of VHT LTFs can be increased when it is performed.

The VHT-SIGB field 470 contains dedicated control information necessary for a plurality of MIMO paired STAs to receive the PPDU 400 and obtain the data. Thus, the STA may be designed to decode the VHT-SIGB field 470 only if the control information contained in the VHT-SIGA field 440 indicates that the PPDU 400 currently received is MU-MIMO transmitted. have. Conversely, if the control information contained in the VHT-SIGA field 440 indicates that the PPDU 400 currently received is for a single STA (including SU-MIMO), the STA does not decode the VHT-SIGB field 470 .

The VHT-SIGB field 470 may include information on a modulation and coding scheme (MCS) and rate-matching for each STA. It may also include information indicating the PSDU length included in the data field for each STA. The information indicating the length of the PSDU is information indicating the length of the bit sequence of the PSDU, and can be indicated in units of an octet. On the other hand, when the PPDU is SU-transmitted, information on the MCS may not be included in the VHT-SIGB field 470 because it is included in the VHT-SIGA field 440. The size of the VHT-SIGB field 470 may vary depending on the type of MIMO transmission (MU-MIMO or SU-MIMO) and the channel bandwidth used for PPDU transmission.

The data field 480 contains data intended for transmission to the STA. The data field 480 includes a service field for initializing a scrambler and a PLCP service data unit (PSDU) to which a MAC Protocol Data Unit (MPDU) is transmitted in the MAC layer, a service field for initializing a convolution encoder, a tail field including a bit sequence necessary for returning the data field to a normal state, and padding bits for normalizing the length of the data field. In the case of MU transmission, the data field transmitted to each STA may include a data unit, each of which is intended to be transmitted, and the data unit may be an aggregate MPDU (A-MPDU).

STA2 22 and STA3 23 when the AP 10 wants to transmit data to the STA1 21, the STA2 22 and the STA3 23 in a given wireless LAN system as shown in Fig. 1, And the STA4 24 to the STA group. In this case, it is possible to allocate no spatial stream allocated to the STA4 24 as shown in FIG. 4, allocate a specific number of spatial streams to each of the STA1 21, the STA2 22 and the STA3 23, Lt; / RTI > In the example shown in Fig. 4, it can be seen that one spatial stream is allocated to STA1 21, three spatial streams are allocated to STA2 22, and two spatial streams are allocated to STA3.

A feature of wireless LAN system supporting MIMO transmission scheme using multiple antennas is that it can improve throughput of system by transmitting several spatial streams. In a situation where a plurality of STAs exist, beamforming to a specific STA to transmit data is required, and channel state information through channel sounding is fed back.

Wireless LAN systems provide two types of channel sounding methods. One is a method based on a PPDU including a data field, and the other is a method based on an NDP (Null Data Packet) having a PPDU format that does not include a data field. When performing channel sounding based on NDP, a PPDU indicating an NDP notification indicating that the NDP is to be transmitted must be transmitted first. This can be implemented by including signaling information indicating the NDP notification in the HT control field of the PPDU, or by transmitting a separately defined NDPA (Null Data Packet Announcement) frame.

5 is a diagram illustrating a channel sounding method using an NDP in a next generation wireless LAN system. In this example, the AP performs channel sounding on three transmission target STAs in order to transmit data to three transmission target STAs. However, the AP may perform channel sounding for one STA.

Referring to FIG. 5, the AP transmits an NDPA frame to STA1, STA2, and STA3 (S510). The NDPA frame indicates that channel sounding is initiated and NDP is to be transmitted. An NDPA frame may be referred to as a sounding announcement frame.

The NDPA frame includes information for identifying a STA to which a channel is estimated and a feedback frame including channel state information is transmitted to the AP. That is, the STA determines whether it is an STA participating in the channel sounding through the reception of the NDPA frame. Accordingly, the AP transmits the STA information field including the information about the STA to be sounded in the NDPA frame. The STA information field may be included for each STA to be sounded.

In order to inform the information for identifying the STA to which the feedback frame is to be transmitted in response to the NDP being transmitted. When transmitting an NDPA frame to at least one target STA for MU-MIMO channel sounding, the AP broadcasts an NDPA frame. On the other hand, when the NDPA frame is transmitted to one target STA for SU-MIMO channel sounding, the AP sets the receiver address information of the NDPA frame to the MAC address of the target STA and transmits the unicast.

Table 2 below shows an example of the STA information field format included in the NDPA frame.

Figure pct00003

In Table 1, Nc indicates the number of columns of the beamforming feedback matrices among the feedback information received by the STA to be sounded in response to the reception of the NDP.

The STAs receiving the NDPA frame can confirm the AID subfield value included in the STA information field and check whether the STA is the sounding STA. 5, the NDPA frame may include an STA information field including the AID of the STA1, an STA information field including the AID of the STA2, and an STA information field including the AID of the STA3.

After transmitting the NDPA frame, the AP transmits the NDP to the target STA (S520). The NDP may have a format in which the data field is omitted in the PPDU format as shown in FIG. The NDP frame is precoded by the AP based on a specific precoding matrix and transmitted to the STA to be sounded. Therefore, the sounding STAs estimate the channel based on the VHT-LTF of the NDP and obtain the channel state information.

The length information indicating the length of the PSDU included in the data field or the length of the A-MPDU (Aggregate-MAC protocol data unit) included in the PSDU is set to 0 as NDP control information included in the NDP, The information indicating the number of STAs to be transferred in the STA is set to 1. [ It indicates whether the transmission scheme used for NDP transmission is MU-MIMO or SU-MIMO, and the group ID indicating the STA group to be transmitted is set to a value indicating SU-MIMO transmission. The information indicating the number of spatial streams to be allocated to the STA to be transmitted is set to indicate the number of spatial streams to be transmitted to the STA to be transmitted through MU-MIMO or SU-MIMO. The channel bandwidth information used for the NDP transmission can be set to the bandwidth value used for the NDPA frame transmission.

The STA1 transmits a feedback frame to the AP (S531). The channel bandwidth information used for the feedback frame transmission may be set to be narrower or equal to the channel bandwidth used for the NDPA frame transmission.

After receiving the feedback frame from the STA1, the AP transmits a feedback poll frame to the STA2 (S541). The feedback poll frame is a frame for requesting the receiving STA to transmit the feedback frame. The feedback poll frame is transmitted unicast to the STA requesting the transmission of the feed-packet frame. The STA2 receiving the feedback poll frame transmits a feedback frame to the AP (S532). The AP transmits a feedback poll frame to the STA3 (S542), and the STA3 transmits a feedback frame to the AP in response to the feedback poll frame (S533).

The channel bandwidth for transmitting data in a WLAN system may vary. The channel information for various bandwidths can be fed back to estimate the channel for various bandwidths. The VHT WLAN system supports 20 MHz, 40 MHz, 80 MHz, 160 MHz continuous (contiguous 160 MHz) and discontinuous 160 (80 + 80 MHz) (noncontiguous 160 MHz) bandwidth. Therefore, since the channel information for each bandwidth is fed back, the number of channel feedback information can be increased.

In the present invention, the channel state information according to the channel estimation performed by the STA is included in the feedback frame transmitted by the STA to the AP. The channel state information of the feedback frame may be implemented as a channel information field and a channel information control field. Tables 3 and 4 below show formats of the channel information control field and the channel information field.

Figure pct00004

Figure pct00005

The information of the channel information field described in Table 4 can be interpreted based on the information included in the channel control field described in Table 3. [

Recently, M2M (Machine-to-Machine) technology has come into the spotlight to support a variety of communication services such as smart grid, e-Health, and ubiquitous. Temperature and humidity sensors, and large-scale machines such as cameras, TV appliances, factory machines, and automobiles can all be components of the M2M system. The elements constituting the M2M system can transmit and receive data based on the wireless LAN communication. When the devices constituting the M2M system support the wireless LAN and configure the network, it is referred to as an M2M wireless LAN system in the following.

The characteristics of the wireless LAN system supporting M2M are as follows.

1) Number of STAs: M2M assumes that a large number of STAs exist in the BSS unlike existing networks. This is because not only devices owned by individuals but also sensors such as houses and companies are considered. Therefore, a considerable number of STAs can be connected to one AP.

2) Low traffic load per STA: In the M2M system, the STA has a traffic pattern that collects and reports the surrounding information, so it does not need to be sent frequently and the amount of the information is small.

3) Uplink-oriented communication: M2M mainly receives the command on the downlink and takes action and reports the result data on the uplink. Since the main data is generally transmitted in the uplink, the uplink becomes the center in the system supporting the M2M.

4) Power Management of STA: M2M terminal is mainly battery operated and it is often difficult for users to charge frequently. Therefore, a power management method is required to minimize battery consumption.

5) Auto-recovery function: The device that configures the M2M system needs to be able to recover itself because it is difficult for a person to operate it directly under certain circumstances.

A WLAN standard that uses M2M communication having these characteristics as a use case is being discussed. The distinguishing feature of M2M wireless LAN system is that it has much broader coverage (for example, up to 1km) compared to existing indoor wireless LANs in license-exempt zones below 1GHz except TV WS. That is, when a wireless LAN system is operated in a band below 1 GHz, which is typically 700 to 900 MHz, unlike the conventional wireless LAN system using the 2.4 GHz or 5 GHz band, Is expanded by two to three times. In this case, a very large number of STAs can be connected per AP. An example of the use of M2M wireless LAN system is as follows.

Use case 1: sensors and meters

1a: Smart Grid - meter to pole for polling

1c: Environmental / agricultural monitoring.

1d: industrial process sensors

1e: Healthcare

1f: Healthcare

1g: home / building automation

1h: home sensors (home sensors)

Use case 2: Backhaul sensor and meter data

Backhaul aggregation of sensors

Backhaul aggregation of industrial sensors

Use Case 3: Extended range Wi-Fi (extended range)

Outdoor extended range hotspot

Outdoor Wi-Fi for cellular traffic offloading (outdoor Wi-Fi for cellular traffic offloading)

The sensor and meter according to the use example 1 may be a representative example of the above-mentioned M2M-supported wireless LAN communication. Accordingly, various types of sensor devices can be connected to a wireless LAN AP to perform M2M-based communication. In particular, up to 6000 sensor devices can be connected to one AP in the case of Smart Grid.

Use Case 2 In the case of backhaul sensor and meter data, an AP providing wide coverage serves as a backhaul link for other systems such as IEEE 802.15.4g.

Use case 3 is intended for outdoor extended range hotspot communication such as extended home coverage, campus wide coverage, shopping mall, and the case where the AP is used for traffic of cellular mobile communication And offloading to distribute the overloaded cellular traffic.

6 is a diagram illustrating an example of channelization of an M2M wireless LAN system according to each country / region band plan.

Referring to FIG. 6, it can be seen that various types of channelization can be applied because the available frequency bands in the sub-1 GHz band are different from each country / region. In the case of the US with the largest available frequency band, as shown in FIG. 6, it can be seen that up to a channel bandwidth of 16 MHz can be used when the minimum bandwidth is 1 MHz. In this way, the M2M wireless LAN system transmits and receives data using a very small channel bandwidth compared to the existing wireless LAN system.

On the other hand, in an environment in which a BSS provided by an AP, such as an M2M wireless LAN system, has a wide coverage and a plurality of STAs can be connected to the AP, a narrow band channel transmission channel transmission may be effective. However, operating the entire BSS as a single narrowband channel can add to interference and fading risk.

In a narrowband frequency environment such as a wireless LAN system, a frequency selective channel access mechanism may be required.

FIG. 7 is a diagram illustrating a concept of a frequency selective channel access mechanism in a narrowband frequency environment of an M2M wireless LAN system according to an embodiment of the present invention. Referring to FIG.

The frequency selective channel access means selecting and transmitting a subchannel with the best SNR when there is a large difference in signal to noise ratio (SNR) for each subchannel.

Referring to FIG. 7, channel N corresponds to an 8 MHz channel including four 2 MHz subchannels. It can be seen that the SNR is large for each of the four subchannels. In this case, it is preferable to transmit the PPDU using the subchannel 1 having the highest SNR. In M2M wireless LAN system

In order to apply the transmission / reception method based on the frequency selective channel access to the wireless LAN system, a procedure for selecting a subchannel with the highest SNR among a plurality of subchannels is required. Specifically, it is required that each STA reports the channel quality of each subchannel to the AP, and that the AP can selectively allocate the best channel for each STA.

In the present invention, in an environment where the BSS operates in a relatively larger BSS bandwidth, the AP allocates the best available subchannel to each STA and transmits the data frame to at least one STA . Transmitting a data frame to at least one STA may be by transmitting a data frame in a DL-FDMA (Downlink-Frequency Division Multiple Access) type. That is, the DL traffic can be transmitted in the form of DL-FDMA from the AP to all the subchannels, but the STA transmits a frame for UL traffic to a specific allocated subchannel.

8 is a diagram illustrating an example of a channel used in a wireless LAN system according to an embodiment of the present invention.

Referring to FIG. 8, each subchannel CH1, CH2, CH3 or CH4 may itself refer to a different 2 MHz channel. In addition, for example, CH1 & CH2 refers to a 4 MHz channel combining CH1 and CH2. CH1 & CH2 & CH3 & CH4 refers to an 8 MHz channel combining all of CH1 to CH4. 8 is one example for convenience in explaining the embodiment of the present invention. However, the DL-FDMA mechanism proposed in the present invention can be extended to other general channelization . In particular, subchannels, which also refer to non-contiguous channels, may be used as they are non-contiguous. For example, DL-FDMA transmission proposed in the present invention may be possible for a discontinuous 4 MHz channel of CH1 & CH3.

Hereinafter, a method of transmitting and receiving a frame based on DL-FDMA in the above-described channel situation will be described in detail.

9 is a diagram illustrating a DL-FDMA-based frame transmission / reception method according to an embodiment of the present invention.

Referring to FIG. 9, the AP performs contention for a channel access and obtains access rights to a corresponding band for an entire 8 MHz band.

The AP transmits an NDPA frame informing the NDP transmission (S910). The NDPA frame is transmitted in four duplicated PPDU formats in 2MHz subchannel units. As in the NDP-based channel sounding method described above with reference to FIG. 5, the NDPA frame includes information for identifying a STA to estimate a channel and transmit a feedback frame including channel state information to the AP. That is, information indicating the STAs that should respond to the NDP. The information indicating STAs may include indicators that STAs are grouped to indicate the group or indicators that indicate individual STAs. The indicator indicating the individual STA may be part or all of the STA's AID.

The AP transmits an NDP frame following the NDPA frame (S920). NDP is transmitted in 4 duplicated PPDU formats in 2MHz subchannel units as in NDPA. Each STA can obtain channel state information based on the NDP.

Upon completion of the NDP transmission, the STA1, which is the first to respond to the NDP after a predetermined interval such as SIFS (Short InterFrame Space), transmits a feedback frame including channel state information to the AP (S932). The channel state information transmitted to the AP through the feedback frame can be implemented as shown in Tables 3 and 4 above. The channel state information is transmitted including information on the beamforming feedback matrix V for each subcarrier index and information on an average SNR for each spatial stream. The channel state information may include channel related information for each 2MHz subchannel. I.e., information related to the average SNR value for each 2MHz subchannel.

When the AP receives the feedback frame, the AP can determine the channel to be used for the data frame transmission to the STA1 based on the channel state information included in the feedback frame received from the STA1. The AP may determine that the subchannel with the highest SNR value estimated by STA1 is allocated for STA1. Or to assign a subchannel whose STA1 estimated SNR value is above a certain threshold value for STA1. Hereinafter, the above-described method can also be applied to receiving a feedback frame from STA2 to STA4 and determining a subchannel to be allocated to the STA.

If the AP decides to use both CH1 and CH4 when transmitting data frames to STA1, it may not perform polling to receive feedback frames from other STAs (STA2, STA3 and / or STA4).

If the STA1 transmits a data frame using a particular subchannel among CH1 to CH4, the AP can perform polling through transmission of a feedback poll frame. The AP transmits a feedback poll frame requesting to transmit a feedback frame including channel state information to the STA2 (S941). The STA2 transmits a feedback frame to the AP in response to the feedback poll frame (S942).

The AP can terminate the polling if it allocates all of the subchannels other than the subchannel allocated to the STA1 to the STA2 and decides to transmit the data frame. However, if it is determined that a certain subchannel is allocated to transmit a data frame, the AP transmits a feedback poll frame requesting to transmit a feedback frame including channel state information to the STA3 (S951). The STA2 transmits a feedback frame to the AP in response to the feedback poll frame (S952).

The AP may terminate the polling if it allocates all of the subchannels other than the subchannels allocated to STA1 and STA2 to STA3 and decides to transmit the data frame. On the other hand, when it is determined to transmit a data frame by allocating some subchannels, the AP transmits a feedback poll frame requesting to transmit a feedback frame including channel state information to the STA4 (S961). The STA4 transmits a feedback frame to the AP in response to the feedback poll frame (S962).

The feedback poll frame transmitted by the AP and the feedback frame transmitted by each STA can be transmitted through the NDPA frame and the entire channel band in which the NDP is transmitted. The feedback poll frame and the feedback frame may be transmitted in an 80 MHz PPDU or in a transmission in an 80 MHz replicated PPDU format.

Assigning subchannels to each STA belonging to a particular STA group through the above scheme can be implemented in various ways. In the present embodiment, however, it is assumed that STA1 is allocated to CH2, STA2 to CH4, STA3 to CH1, and STA4 to CH3.

After determining the best subchannel for each STA, the AP obtains the access right for the entire band of 8 MHz through competition and transmits the PPDU to the STA1 to STA4 in the DL-FDMA transmission scheme (S970). The transmission of the PPDU in the DL-FDMA transmission scheme is performed by transmitting different data frames to each STA for each channel allocated to each STA. If the transmission length of the data frame to be transmitted to each STA does not match, the length of the PPDU is adjusted based on the length of the longest data frame. That is, if the length of a data frame to be transmitted to a specific STA over a specific channel is shorter than the length of a reference data frame, null padding can be performed for a short length.

The preamble portion of the DL-FDMA PPDU may include subchannel allocation information indicating which subchannel is allocated to each STA. In other words, in the preamble portion, the STA indicating that the data frame for each subchannel is data intended to be transmitted to which STA, the STAs that have previously responded to the NDP with the feedback frame can confirm which subchannel is allocated to the STA. Therefore, each STA can decode only the corresponding sub-channel part allocated thereto and acquire the data.

The subchannel allocation information may be implemented by indicating which CH is allocated to the STA by the 3-bit sequence allocated to each STA. Specifically, the subchannel allocation information can be implemented as shown in Table 5 below.

Figure pct00006

If the channel allocation information is included in the preamble for each STA, a total of 12 bits of bit space is required. That is, the channel allocation information for the STAs may be implemented in a 12-bit sequence in the preamble. However, the above-described channel allocation information is not an example, and when more subchannels are allocated, more bits can be allocated to each STA, and less bits can be allocated to a subchannel allocation more simply Lt; / RTI > Also, in the channel allocation example of Table 5, when two or more subchannels are allocated, the subchannels may have continuous characteristics, but non-continuous channels may be allocated.

After the PPDU transmission is completed, the STA transmits an ACK frame through a subchannel allocated thereto after a specific interval such as SIFS (S980). STA1 to STA4 transmit ACK frames simultaneously after receiving PPDUs. The PPDU transmission / reception through the DL-FDMA transmission scheme is terminated. If an AP does not receive an ACK from a particular STA, a separate data frame retransmission may be made via a subchannel allocated to a particular STA.

Meanwhile, in the data frame transmission / reception method based on the DL-FDMA transmission technique as described above, subchannels can be allocated to the STA in addition to the channel sounding method as described above. In the embodiment of FIG. 9, the channel assigned to the STA is determined by the AP, but it is determined that the channel to be allocated by the STA is requested and information about the channel may be signaled to the AP. In this case, the AP can transmit the data frame based on the channel allocation information received from the STA.

The determination of the subchannels to be allocated to each STA can be implemented through RTS-CTS frame exchange. The AP transmits an RTS frame over the entire channel band to a specific STA. The RTS frame can be transmitted in the PPDU format replicated in units of subchannels. The STA receiving the RTS frame may signal to the AP for the subchannel with the highest SNR value or one or more subchannels that exceed a certain SNR threshold. For this purpose, the STA transmits a CTS frame of the copied PPDU format to the AP. An individual CTS frame transmitted on a subchannel allocated by the STA may be transmitted together with information indicating that the corresponding subchannel is a subframe requested to be allocated by the STA. The indication information may be implemented with a one-bit indication bit indicating whether or not allocation is requested. The indication information may be included in an initial scrambling sequence on which the individual CTS frame is scrambled.

An AP may perform an RTS-CTS frame exchange procedure on one or more STAs. Thus, the AP may obtain information on the subchannels for which allocation is requested from one or more STAs. The AP can allocate subchannels to each STA based on the obtained information and transmit the data frame through the DL-FDMA transmission scheme. The information about the subchannel allocated to the STA and the transmission of the PPDU according to the DL-FDMA transmission scheme can be implemented as shown in FIG.

10 is a block diagram illustrating a wireless device to which an embodiment of the present invention may be applied. The wireless device may be an AP or STA.

The wireless device 1000 includes a processor 1010, a memory 1020, and a transceiver 1030. The transceiver 1030 transmits / receives radio signals, but the physical layer of IEEE 802.11 is implemented. The processor 1010 is functionally coupled to the transceiver 1030 to implement the MAC and physical layers of IEEE 802.11. The processor 1010 is configured to implement a data frame transmission / reception method based on a channel access mechanism according to an embodiment of the present invention. The processor 1010 may be configured to determine a subchannel to allocate to a particular recipient via the NDP sounding method. The processor 1010 may be configured to transmit data frames in the DL-FDMA transmission scheme through the assigned sub-channels. The processor 1010 may be configured to transmit information on the subchannel allocated to the receiver by including it in the preamble portion of the PPDU including the data frame transmitted in the DL-FDMA transmission scheme. The processor 1010 may be configured to implement the embodiment of the present invention described above with reference to Figures 6-9.

Processor 1010 and / or transceiver 1030 may comprise an application-specific integrated circuit (ASIC), other chipset, logic circuitry and / or data processing device. Memory 1020 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. When the embodiment is implemented in software, the above-described techniques may be implemented with modules (processes, functions, and so on) that perform the functions described above. The module may be stored in memory 1020 and executed by processor 1010. The memory 1020 can be internal or external to the processor 1010 and can be coupled to the processor 1010 in a variety of well known ways.

Claims (15)

  1. A method for transmitting a data frame over a channel including a plurality of subchannels performed by a sender in a wireless LAN system,
    Acquiring first channel state information for each of the plurality of subchannels from the first receiver;
    Allocating at least one first allocated subchannel among the plurality of subchannels to a first receiver based on the first channel state information;
    Acquiring second channel state information for each of the plurality of subchannels from the second receiver if the at least one first allocated subchannel corresponds to a portion of the plurality of channels;
    Allocating at least one second assigned subchannel among the plurality of subchannels to a second recipient based on the second channel state information; And
    And transmitting the data unit to the first receiver and the second receiver,
    The data unit comprising a first data frame and a second data frame,
    Wherein the first data frame is transmitted over the at least one first allocated subchannel, and
    And the second data frame is transmitted through the at least one second allocated subchannel.
  2. The method according to claim 1,
    Wherein the data unit further includes a preamble part, and the preamble includes subchannel allocation indication information indicating a subchannel allocated to the first receiver and the second receiver. .
  3. The method according to claim 1,
    Wherein the first channel state information comprises an estimated SNR (Signal to Noise Ratio) between the sender and the first receiver for each subchannel, and
    Wherein the second channel state information includes an estimated SNR between the sender and the second receiver for each subchannel.
  4. The method of claim 3,
    Allocating the at least one first allocated subchannel to the first receiver allocates a specific subchannel having the highest estimated SNR between the sender and the first receiver to the first assigned subchannel; Wherein the data frame is transmitted at a predetermined rate.
  5. 4. The method of claim 3, wherein allocating the at least one first allocated subchannel to the first receiver further comprises: allocating at least one or more subchannels with an estimated SNR higher than a certain threshold value between the sender and the first receiver And assigning the first subchannel to the first assigned subchannel.
  6. The method according to claim 1,
    Obtaining the first channel state information comprises:
    Transmits an NDPA (NDP Announcement) frame indicating that NDP (Null Data Packet) for channel sounding is transmitted;
    Transmit the NDP; And
    And receiving, from the first receiver, a first feedback frame including the first status channel information obtained based on the NDP.
  7. 7. The method of claim 6, wherein the obtaining of the second channel state information comprises:
    Send a feedback poll frame to said second receiver indicating to report said second channel state information; And
    And receiving, from the second receiver, a second feedback frame including the second status channel information obtained based on the NDP.
  8. 8. The method of claim 7, wherein the NDPA frame includes information identifying the first receiver and the second receiver, which are recipients of the channel sounding.
  9. 9. The method of claim 8, wherein the NDPA frame is transmitted in a duplicated data unit format transmitted simultaneously through each of the plurality of subchannels.
  10. 10. The method of claim 9, wherein the NDP is transmitted in the replicated data unit format transmitted through each of the plurality of subchannels.
  11. The method of claim 1, wherein the at least one second allocated subchannel is selected from among the plurality of subchannels except for the at least one first allocated subchannel.
  12. 2. The method of claim 1, further comprising: if the at least one first assigned subchannel is allotted to the plurality of channels, transmitting the first data frame to the first recipient over the channel Wherein the data frame is transmitted at a predetermined rate.
  13. The method according to claim 1,
    Receive a first acknowledgment frame in response to the first data frame on the at least one first allocated subchannel; And
    And receiving a second acknowledgment frame in response to the second data frame on the at least one second allocated subchannel.
  14. 14. The method of claim 13,
    Wherein the first acknowledgment frame and the second acknowledgment frame are simultaneously transmitted.
  15. A wireless device operating in a wireless LAN system,
    A transceiver for transmitting and receiving a radio signal through a channel including a plurality of subchannels; And
    And a processor operatively coupled to the transceiver,
    Acquiring first channel state information for each of the plurality of subchannels from the first receiver,
    Allocating at least one first allocated subchannel among the plurality of subchannels to a first receiver based on the first channel state information,
    Acquiring second channel state information for each of the plurality of subchannels from the second receiver if the at least one first allocated subchannel corresponds to a portion of the plurality of channels,
    Allocating at least one second allocated subchannel among the plurality of subchannels to a second receiver based on the second channel state information, and
    Data unit to a first recipient and a second recipient,
    The data unit comprising a first data frame and a second data frame,
    Wherein the first data frame is transmitted over the at least one first allocated subchannel, and
    Wherein the second data frame is transmitted over the at least one second allocated subchannel.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016039526A1 (en) * 2014-09-12 2016-03-17 엘지전자(주) Method for transmitting data in wlan system, and device for same

Families Citing this family (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011001911A1 (en) * 2011-04-08 2012-10-11 Rheinisch-Westfälische Technische Hochschule Aachen Method for a transmitter for a multichannel communication system for sending real-time sensitive data D
US9295033B2 (en) * 2012-01-31 2016-03-22 Qualcomm Incorporated Systems and methods for narrowband channel selection
JP5754815B2 (en) * 2012-07-06 2015-07-29 日本電信電話株式会社 Wireless communication system and wireless communication method
AU2013378208B2 (en) 2013-02-15 2016-02-25 Lg Electronics Inc. Method and device for transmitting/receiving frame in accordance with bandwidth thereof in WLAN system
KR20140133480A (en) 2013-05-10 2014-11-19 한국전자통신연구원 Method for channel sounding in wireless local area network and apparatus for the same
KR20160010431A (en) 2013-05-14 2016-01-27 엘지전자 주식회사 Method for supporting basic service set in wireless lan system and apparatus therefor
CN104185296B (en) * 2013-05-20 2018-02-06 华为技术有限公司 Channel access method and access point
TWI669021B (en) * 2013-06-06 2019-08-11 內數位專利控股公司 Device and method for wifi channel selection and subchannel selective transmissions
US9838093B2 (en) * 2013-08-06 2017-12-05 Electronics And Telecommunications Research Institute Method of transmitting and receiving frame for uplink multi-user multiple-input and multiple-output (UL MU-MIMO) communication
US10051660B2 (en) * 2013-10-03 2018-08-14 Qualcomm Incorporated Virtual carriers for LTE/LTE-A communications in a shared spectrum
WO2015065160A1 (en) * 2013-11-04 2015-05-07 한국전자통신연구원 Method and apparatus for performing wireless communication on the basis of frequency selective transmission in wireless local area network (wlan)
KR20150051911A (en) 2013-11-04 2015-05-13 한국전자통신연구원 Method and apparatus for wireless communicating based on frequency selective transmission in wireless local area network
US9814092B2 (en) * 2013-12-20 2017-11-07 Electronics And Telecommunications Research Institute Frame transmission method performed in access point, frame reception method performed in terminal, and access point
US9680563B2 (en) * 2014-01-17 2017-06-13 Apple Inc. System and method for partial bandwidth communication
US9774436B2 (en) 2014-01-30 2017-09-26 Intel IP Corporation Systems, methods and devices for selective interference coordination in a cellular protocol
WO2015119374A1 (en) * 2014-02-10 2015-08-13 엘지전자 주식회사 Method and device for transmitting frame in wireless lan
WO2015156495A1 (en) * 2014-04-09 2015-10-15 엘지전자 주식회사 Method and apparatus for transmitting frame on basis of sounding procedure
EP3136807A4 (en) * 2014-04-21 2017-12-20 Kabushiki Kaisha Toshiba Integrated circuit for radio communication
US20150372795A1 (en) * 2014-06-18 2015-12-24 Mediatek Singapore Pte. Ltd. CSI Feedback Modes and Indication for Sub Channel Feedback in OFDMA Systems
KR20160004950A (en) * 2014-07-04 2016-01-13 뉴라컴 인코포레이티드 Frame transmitting method and frame receiving method
EP3152854A4 (en) * 2014-07-08 2017-12-20 MediaTek Inc. Methods for providing concurrent communications among multiple wireless communications devices
US20170202019A1 (en) * 2014-07-09 2017-07-13 Lg Electronics Inc. Method and terminal for receiving data through unlicensed band in mobile communication system
US9408184B2 (en) * 2014-08-01 2016-08-02 Newracom, Inc. Systems and methods for multi-user simultaneous transmissions
KR20160022790A (en) * 2014-08-20 2016-03-02 뉴라컴 인코포레이티드 Physical layer protocol data unit format includiing padding in a high efficiency wireless lan
US10432364B2 (en) 2014-08-22 2019-10-01 Lg Electronics Inc. Method and apparatus for performing signaling for reserved sub-band in wireless communication system
US10200165B2 (en) * 2014-10-06 2019-02-05 Newracom, Inc. Beamformed transmission in high efficiency wireless LAN
US20160119927A1 (en) * 2014-10-24 2016-04-28 Newracom, Inc. Ofdma resource assignment rules to achieve robustness
CN105874858B (en) 2014-12-05 2019-05-03 华为技术有限公司 The channel multiplexing method and device of multi-transceiver configuration method, multi-transceiver
US9907073B2 (en) * 2014-12-08 2018-02-27 Newracom, Inc. Efficient DL OFDMA frequency selectivity harvesting
US20160192351A1 (en) * 2014-12-26 2016-06-30 Newracom, Inc. Systems and methods for multi-user transmission
US10075873B2 (en) * 2015-03-02 2018-09-11 Qualcomm Incorporated Methods and apparatus for channel state information sounding and feedback
WO2016163639A1 (en) * 2015-04-08 2016-10-13 엘지전자 주식회사 Method and apparatus for protecting medium in wireless lan
KR20170117445A (en) * 2015-04-16 2017-10-23 엘지전자 주식회사 Method and apparatus for channel sounding in a wireless communication system
SG11201708608YA (en) * 2015-04-20 2017-11-29 Agency Science Tech & Res Method and apparatus for broadcast geo-location database (gldb) for television white space (tvws) spectrum access
JP2018101820A (en) * 2015-04-23 2018-06-28 株式会社東芝 Radio terminal and radio communication method
US9730151B2 (en) * 2015-04-24 2017-08-08 Qualcomm Incorporated Method and apparatus for initiating channel sounding with unassociated access points
WO2016173103A1 (en) * 2015-04-30 2016-11-03 华为技术有限公司 Resource indication method and apparatus for wlan system
WO2016183749A1 (en) * 2015-05-15 2016-11-24 华为技术有限公司 Sub-signaling segment processing method, processing device, access point, and station
US9872306B2 (en) 2015-06-02 2018-01-16 Qualcomm, Incorporated Efficient optimal group id management scheme for MU-MIMO systems
EP3301963A4 (en) * 2015-07-02 2018-05-02 Huawei Technologies Co., Ltd Method for transmitting channel state information, access point, and station
KR20170025918A (en) * 2015-08-31 2017-03-08 삼성전자주식회사 A method and apparatus for service based on a location
US10225866B2 (en) * 2015-09-16 2019-03-05 Qualcomm Incorporated Systems, methods, and devices for enhanced OFDMA random access
CN105554853B (en) * 2015-12-31 2019-01-11 陕西烽火电子股份有限公司 A kind of optimization method of shortwave booting communication
CN106953721A (en) * 2016-01-07 2017-07-14 华为技术有限公司 A kind of transmission method and device of extended distance pattern
US20180234135A1 (en) * 2017-02-15 2018-08-16 Qualcomm Incorporated Distributed multi-user (mu) wireless communication
WO2019120563A1 (en) * 2017-12-22 2019-06-27 Huawei Technologies Co., Ltd. Devices and methods for ndp feedback

Family Cites Families (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4422389B2 (en) 2002-05-24 2010-02-24 シャープ株式会社 Wireless communication system and terminal station
CA2596997C (en) 2005-02-04 2015-07-14 Kabushiki Kaisha Toshiba Optimal channel assignment for multi-class, multi-channel wireless lans and the like
US8830846B2 (en) * 2005-04-04 2014-09-09 Interdigital Technology Corporation Method and system for improving responsiveness in exchanging frames in a wireless local area network
KR100643299B1 (en) 2005-06-09 2006-10-31 삼성전자주식회사 Method and apparatus for transmitting and receiving legacy format data in high throughput wireless network
TW200705901A (en) * 2005-06-09 2007-02-01 Samsung Electronics Co Ltd Method and apparatus for receiving data with down compatibility in high throughput wireless network
KR100703287B1 (en) * 2005-07-20 2007-04-03 삼성전자주식회사 System and method for transmitting/receiving resource allocation information in a communication system
US8787841B2 (en) * 2006-06-27 2014-07-22 Qualcomm Incorporated Method and system for providing beamforming feedback in wireless communication systems
US8363607B2 (en) 2006-09-11 2013-01-29 Qualcomm Incorporated VOIP group resource management
EP2068578B1 (en) * 2006-09-29 2013-02-27 Mitsubishi Electric Corporation Channel assignment notifying methods
US8363627B2 (en) * 2007-06-19 2013-01-29 Intel Corporation Modulation coding schemes for control frame transmission under 802.11N
KR100916242B1 (en) * 2007-07-31 2009-09-10 전자부품연구원 Wireless communication system and communicating method thereof
CN101527591A (en) 2008-03-07 2009-09-09 富士通株式会社 Method for selecting sub-channel mode and MIMO communication system applying same
KR101404275B1 (en) * 2008-05-30 2014-06-30 엘지전자 주식회사 Channel allocation mechanism of PPDUs for Very High Throughput (VHT) wireless local access network system and station supporting the channel allocation mechanism
KR101452504B1 (en) * 2008-06-18 2014-10-23 엘지전자 주식회사 Channel access mechanism for Very High Throughput (VHT) wireless local access network system and station supporting the channel access mechanism
JP2010041581A (en) * 2008-08-07 2010-02-18 Hitachi Communication Technologies Ltd Wireless communication system, communication method and base station
US20100091731A1 (en) 2008-10-13 2010-04-15 Samsung Electronics Co., Ltd. Channel allocation method and apparatus for wireless communication networks
KR101240352B1 (en) * 2008-12-09 2013-03-08 한국전자통신연구원 Apparatus and method for allocating resource in wireless communication system
KR101289944B1 (en) 2008-12-12 2013-07-26 엘지전자 주식회사 Method for channel estimation in very high throughput wireless local area network system and apparatus for the same
WO2010120692A1 (en) 2009-04-13 2010-10-21 Marvell World Trade Ltd. Physical layer frame format for wlan
US9197298B2 (en) * 2009-06-05 2015-11-24 Broadcom Corporation Group identification and definition within multiple user, multiple access, and/or MIMO wireless communications
US9048895B2 (en) * 2009-06-05 2015-06-02 Broadcom Corporation Multi-user null data packet (MU-NDP) sounding within multiple user, multiple access, and/or MIMO wireless
KR101534865B1 (en) 2009-06-23 2015-07-27 엘지전자 주식회사 Method of performing link adaptation procedure
EP2465227B1 (en) 2009-08-12 2017-07-26 Marvell World Trade Ltd. Sdma multi-device wireless communications
US9112741B2 (en) 2009-09-18 2015-08-18 Qualcomm Incorporated Protocol to support adaptive station-dependent channel state information feedback rate in multi-user communication systems
US8422449B2 (en) * 2009-10-23 2013-04-16 Electronics And Telecommunications Research Institute MU-MIMO method in WLAN system, and access point and station for MU-MIMO
US9119110B2 (en) * 2010-09-22 2015-08-25 Qualcomm, Incorporated Request to send (RTS) and clear to send (CTS) for multichannel operations
US20130058239A1 (en) * 2010-10-21 2013-03-07 James June-Ming Wang Integrity and Quality Monitoring and Signaling for Sounding and Reduced Feedback
US8730905B2 (en) * 2010-11-04 2014-05-20 Nokia Corporation Transmission resource reservation scheme
US9820304B2 (en) * 2011-01-11 2017-11-14 Intel Corporation Transmission rules within a TXOP for wider bandwidth operation
US20140092860A1 (en) * 2011-06-16 2014-04-03 Nokia Corporation Channel reservation in wireless network
US9066265B2 (en) * 2012-10-19 2015-06-23 Intel Corporation Methods and arrangements for frequency selective transmission

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016039526A1 (en) * 2014-09-12 2016-03-17 엘지전자(주) Method for transmitting data in wlan system, and device for same
US10075269B2 (en) 2014-09-12 2018-09-11 Lg Electronics Inc. Method for transmitting data in WLAN system, and device for same

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